NAME
alarm - set an alarm clock for delivery of a signal
SYNOPSIS
#include <unistd.h>
unsigned int alarm(unsigned int seconds);
DESCRIPTION
alarm() arranges for a SIGALRM signal to be delivered to the calling
process in seconds seconds.
If seconds is zero, no new alarm() is scheduled.
In any event any previously set alarm() is canceled.
RETURN VALUE
alarm() returns the number of seconds remaining until any previously
scheduled alarm was due to be delivered, or zero if there was no
previously scheduled alarm.
CONFORMING TO
SVr4, POSIX.1-2001, 4.3BSD.
NOTES
alarm() and setitimer(2) share the same timer; calls to one will
interfere with use of the other.
sleep(3) may be implemented using SIGALRM; mixing calls to alarm() and
sleep(3) is a bad idea.
Scheduling delays can, as ever, cause the execution of the process to
be delayed by an arbitrary amount of time.
SEE ALSO
gettimeofday(2), pause(2), select(2), setitimer(2), sigaction(2),
signal(2), sleep(3), time(7)
COLOPHON
This page is part of release 3.24 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.